According to Microsoft's Azure status page, the problems started around 5pm Pacific time and have still not been fully solved. "We are experiencing a connectivity issue across multiple Azure Services," the page said. (http://azure.microsoft.com/en-us/status/#current)

"Microsoft is investigating an issue affecting access to some Microsoft services," said a Microsoft spokesperson. "We are working to restore full access to these services as quickly as possible."

Azure outages are a serious problem for Microsoft as the company tries to sell its cloud-computing service as a cost-effective and reliable alternative to Amazon.com Inc's competing service called AWS.

They are also a headache to the many customers relying on Azure to host websites. That includes Microsoft itself, whose MSN.com site was inaccessible on Tuesday.